There are a number of types of different interval timer mechanisms. Such mechanisms may provide for a single output such as an audible sound or the closing or opening of a pair of electrical contacts upon expiration of a predetermined timed interval. Many of these mechanisms have been used in the past with a presettable period of runout to a timed-out position by initiating an operation to be timed by a push button release or a pointer on a manually actuated winding knob drivingly connected to the timer mechanism. To limit the period of runout to a timed-out position for controlling a given operation, it has been customary to provide different timers each presettable to different maximum timed intervals or which are simply adjustable by the user to variable dial settings. However, a user having a one hour or two hour timer and desiring to repeatedly and reliably preset a longer timing cycle, by simply actuating a winding knob against a stop, will have need for a different timer. Such need may be reflected, for example, in an operation such as changing an energy conservation program in a public or commercial building.